@Beta public interface Service
start()
and
stop()
lifecycle methods to transfer into and out of this state.
Example services include webservers, RPC servers and timers. The normal
lifecycle of a service is:
Service.State.NEW
->Service.State.STARTING
->Service.State.RUNNING
->Service.State.STOPPING
->Service.State.TERMINATED
Service.State.FAILED
, and its behavior is undefined. Such a service cannot be
started nor stopped.
Implementors of this interface are strongly encouraged to extend one of the abstract classes in this package which implement this interface and make the threading and state management easier.
com.google.common.base.Service
)Modifier and Type | Interface and Description |
---|---|
static class |
Service.State
The lifecycle states of a service.
|
Modifier and Type | Method and Description |
---|---|
boolean |
isRunning()
Returns
true if this service is running. |
ListenableFuture<Service.State> |
start()
If the service state is
Service.State.NEW , this initiates service startup
and returns immediately. |
Service.State |
startAndWait()
Initiates service startup (if necessary), returning once the service has
finished starting.
|
Service.State |
state()
Returns the lifecycle state of the service.
|
ListenableFuture<Service.State> |
stop()
|
Service.State |
stopAndWait()
Initiates service shutdown (if necessary), returning once the service has
finished stopping.
|
ListenableFuture<Service.State> start()
Service.State.NEW
, this initiates service startup
and returns immediately. If the service has already been started, this
method returns immediately without taking action. A stopped service may not
be restarted.Future.get()
will block
until the service has finished starting, and returns one of Service.State.RUNNING
, Service.State.STOPPING
or Service.State.TERMINATED
. If
the service fails to start, Future.get()
will throw an
ExecutionException
, and the service's state will be Service.State.FAILED
. If it has already finished starting, Future.get()
returns immediately. Cancelling this future has
no effect on the service.Service.State startAndWait()
start().get()
, this method throws
no checked exceptions, and it cannot be interrupted.UncheckedExecutionException
- if startup failedboolean isRunning()
true
if this service is running.Service.State state()
ListenableFuture<Service.State> stop()
Future.get()
will block
until the service has finished shutting down, and either returns
Service.State.TERMINATED
or throws an ExecutionException
. If
it has already finished stopping, Future.get()
returns
immediately. Cancelling this future has no effect on the service.Service.State stopAndWait()
Service.State.STARTING
, startup will be
cancelled. If this is Service.State.NEW
, it is terminated
without having been started nor stopped. Unlike calling stop().get()
, this method throws no checked exceptions.UncheckedExecutionException
- if shutdown failedCopyright © 2010-2012. All Rights Reserved.